**3. Formation of cave**

*Earth Crust*

**Figure 2.**

*(b) ice cone and ice stalactites, (c) ice stalactites.*

**88**

**Figure 3.**

*(modified from [24]).*

*Top view (a) and geological radar profile (b) of Bailong ice cave at Wudalianchi National Geological Park* 

*The space and interior of Zibaishan ice cave (modified from [23]). (a) The geometry and temperature profile,* 

Caves must be developed before the formation of their internal ice. Cave geometry mainly depended on the lithology of their wall rocks. Two types of lithology were involved in these three ice caves: limestone and basalt.
